Electrical switch



Feb. 11,1941. R, N. GARREY 2,231,115

ELECTRICAL swmcn Filed July 18, 1958 g 17 fuk I INSULA TloN INVENTOR ATTO RN EYS Patented Feb. 11, 1941 UNITED STATES Param* 3 Claims.

This invention relates to electric switches and has for an object to provide a thermo-controlled switch for opening the ignition circuit of automotive vehicles in the event the ignition switch is inadvertently left closed with the motor not running and the contact points in circuit closing position.

When the ignition switch is left on and the motor is not running, the contact points being closed, a short circuit is created between the distributor and battery. This short circuit drains the battery and shortens the life of the same while at the same time the spark is reduced because the ignition points become burned or pitted.. Also the ignition coil and `condenser become weakened and frequently burn out.

The present invention eliminates the above dem scribed disadvantages by breaking the short circuit within three to five minutes after the ignition switch has been inadvertently left on while the motor is not running.

A further object of the invention is to provide a device of this character which will be formed of a few strong simple and durable parts, which will be inexpensive to manufacture, and which will not easily get out of order.

With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to within the scope of the appended claims without departing from the spirit or sacriiicing any of the advantages of the invention.

In the accompanying drawing forming part of this specification,

Figure 1 is a plan View of a thermo-controlled electric switch constructed in accordance with the invention.

Figure 2 is an end elevation of the switch locking towards the right side of Figure 1.

Figure 3 is a front elevation of the switch shown in Figure l with parts in section.

Referring now to the drawing in which like characters of reference designate similar parts in rthe various views, I designates a rectangular base formed of suitable insulating material, having mounted thereon, adjacent its opposite sides, a pair of posts II and I2, also formed of insulating material.

Bolted or otherwise secured adjacent the upper end of the post II is a bimetallic thermo element I3 of substantially horse shoe shape adapted to contract diagonally across its rounded portion so as to move the free end ifi toward the fixed end I5.

A conductor bar I 5 is secured to the base by a binding ypost I to which a conductor wire IS from g the ignition switch is attached. The conductor 'o bar is mounted on the base diametrically opposite the post II to which the thermo element is secured, as best shown in Figure 1.

A resistance coil I9 is secured at one end to the conductor bar by a screw 2D or other connector', and is secured at its opposite end to the post Ii by a kscrew 2I or other connector, and this resistance coil is in contact substantially throughout its length with the thermo element I 3.

The thermo element is provided at its free end with an arm 22 formed of insulating material, to which is attached one end of a helical spring 23. The opposite end of the spring is attached to a switch lever 24 which is pivotally mounted on the post I2. The spring tends to pull the switch lever open.

A contact point, formed by a screw 25, is mounted on the post adjacent the lever and this Contact point is engaged by the lever when the 2- latter lis in circuit closing position. A conductor Wire 26 is connected at one end to the contact point 25 and at the other end is connected to the thermo element I3 through the medium of a screw 26.

The lever 24 is provided with a hub 25 which is o mounted on an adjusting screw 26a carried by the post I2. A brush 21 in the nature of a resilient length of wire has wiping contact with the hub and is secured to the post I 2 through the medium 3 of a binding post 28 to which a wire 29 from the distributor is connected.

When the lever 24, which forms a movable switch arm, is in circuit closing position, a circuit may be traced from the ignition wire i8, through the resistance coil I9, wire 26, contact point 25, lever 24, hub 25' of the lever, brush 21, binding post 28 and wire 29 to the distributor. This is the normal position of the parts.

When the ignition switch has been inadvertently left closed by the driver while the motor is not running and the contact points of the distributor are in engagement with each other, the resistance coil is heated and heats the thermo element which contracts, adding to the tension of the spring 23, against the switch lever 24, suiciently to move the lever away from the contact point 25 to break the circuit to the distributor points. V/'hen the coil I9 cools the retraction of the thermo element I3 is insufficient to deform 55 the spring 23 again and move the lever 24 to circuit closing position thus the ignition circuit remains open.

For adjusting the device to operate eciently in either summer or winter months, a helical spring 30 is sleeved on the adjusting screw 26, between a loose insulating collar 3| on the screw, and a collar 32 which is xed to the screw. The screw is equipped with a button 33 through the medium of which the screw may be advanced or retracted to regulate the pressure of the spring 30 upon the insulating collar 3| which latter frictionally bears against the hub 25 of the switch lever 24. Thus during winter months when greater heat is required to operate the thermo element I3 than in summer months the tension of the spring may be diminished while in summer months when less heat is required the tension of the spring may be increased.

For indicating the position of the switch lever 24 a segment bar 34, bearing the characters W at one end and S at the other end, is secured to the base through the medium of a standard 35. A pointer 36 is fixed to a collar 3l on the adjusting screw 25a contiguous to the button 33. Thus by adjusting the screw 26a until the pointer rests on the character W indicating winter or on the character S indicating summer the operator may properly adjust the screw 26a to regulate the pressure of the spring 3G against the loose collar 3| and hub 25 of the switch lever 24. After each operation the device must be manually reset by moving the switch lever 24 back to normal position.

Since the operation of the parts has been described as the description thereof has progressed it is thought that the invention will be fully understood without further explanation.

What is claimed is:

1. An electric switch comprising an insulating base, a pair of posts mounted upon the base also of insulating material, a bimetallic thermo element of substantially horse shoe shape secured at one end to one of the posts and adapted to contract upon application of heat, the other end of the thermo element extending beyond the post, a connector bar having an upstanding portion extending just above the thermo element and secured to the base diametrically opposite the post to which the element is secured, a resistance coil secured at its ends respectively to the connector bar and to said post to which the thermo element is connected and contacting with the thermo element substantially throughout the length of the coil, an arm of insulating material secured to the free end of the thermo element, a circuit closing lever pivoted to the second named post, a helical spring connecting said arm to said lever, a contact mounted on the second named post adjacent the lever, a conductor wire connecting one end of the thermo element and the lever together electrically, and means for attaching circuit wires to the lever and to said connector bar.

2. In a thermo controlled switch, a bimetallic thermo element of substantially horse shoe shape, a resistance coil in contact with said element for heating the element, a circuit closing lever connected to said thermo element to be moved thereby, a shaft upon which the lever is pivoted, said lever having a hub loose on said shaft, an adjustable tension device on said shaft adapted to exert pressure against said hub, and a collar on the shaft against which said hub may be pressed to adjust the device for operation during winter or during summer temperatures.

3. An electric switch comprising an insulating base, a bimetallic thermo element adapted to r contract upon application of heat thereto, a resistance coil adapted to be connected in circuit with the distributor and with the ignition switch of an automotive vehicle and in contact with the thermo element to heat the thermo element, f

a circuit closing switch arm, a spring yieldably connecting the circuit closing switch arm with the thermo element for moving the switch arm when the thermo element contracts to open circuit position, a shaft, a hub for the switch arm loosely mounted on the shaft, a collar xed to the shaft against which the hub bears, and an adjustable spring device mounted on the shaft and exerting tension against the hub to cause the hub to frictionally engage the collar and regulate movement of said circuit closing arm by said thermo element to compensate for variations in summer and winter temperatures.

ROBERT N. GARREY. 

